The present invention relates to an ink cartridge for providing a supply of pressurized ink to an ink-jet printer. More particularly, the present invention relates to a method and apparatus for providing a pressurized supply of ink in response to actuation by a linear actuator.
The use of an ink supply that is separately replaceable from the printhead is disclosed in patent application Ser. No. 08/429,915, entitled "Ink Supply For An Ink-Jet Printer" now U.S. Pat. No. 5,825,387 assigned to the assignee of the present invention. The advantage of this type of ink supply is that it allows the user to replace the ink container without replacing the printhead. The printhead can then be replaced at or near the end of printhead life and not when the ink container is exhausted.
Ser. No. 08/429,915 now U.S. Pat. No. 5,825,387 discloses the use of an ink container that includes a diaphragm pump. The diaphragm pump is actuated by an actuator associated with the ink-jet printer for supplying ink from the ink container to the printhead. The use of a pump associated with the ink container ensures a reliable supply of ink to the ink-jet printhead. An interruption in ink flow to the printhead can result in a reduction in print quality or damage to the printhead. This interruption in the flow of ink to the printhead during operation of the printhead can result in printhead deprime which can result in excessive heating of the printhead. If this printhead heating is severe enough the printhead reliability can be reduced or the printhead can fail. Therefore, it is important that the apparatus used to provide ink from the ink container to the printhead be highly reliable.
The diaphragm pump as disclosed in Ser. No. 08/429,915 now U.S. Pat. No. 5,825,387 includes a chassis and a diaphragm attached to the chassis. Engagement of the diaphragm by an actuator varies the volume of the chamber defined by the chassis and diaphragm. Varying the volume of the chamber allows ink to be selectively drawn into the chamber and selectively expelled from the chamber. Ink is drawn into the chamber from an ink reservoir. Ink expelled from the chamber is transferred to the printhead by way of an ink conduit.
It is important that the ink cartridge for providing pressurized ink to the ink jet printer interact with the printer in such a way that the printer function properly. If the ink cartridge does not interact properly with the printer the printer may not function properly which can result in a reduction of print quality or a reduction in reliability.
Additionally, it is important that the diaphragm pump be highly reliable. The diaphragm pump should be capable of operating over a large number of actuation cycles without leaking. In addition, the ink cartridge should be strong and resistant to rupturing if the ink container is dropped.
The diaphragm on the diaphragm pump should be flexible so that the force required to activate the pump is relatively low. The use of a low activation force diaphragm pump makes it possible to use actuators that have lower output force capability. These lower output force actuators tend to be lower cost than actuators having higher output force requirements, reducing the cost of the printing system. In addition, the use of lower force actuators tends to reduce the cost of a retention system used to secure the ink container to the printer. The use of lower cost retention systems tends to reduce the cost of the printing system.
Finally, the diaphragm pump should provide a consistent discharge volume. This discharge volume should have little variation from ink container to ink container. In addition, the diaphragm pump should be well suited for high volume manufacturing techniques allowing the ink container to be produced at lower cost.